A transformer is switched from one tap to another tap to change the number of turns of an active coil of the transformer at the high-voltage side to achieve the purpose of voltage regulation. An on-load tap-changing switch changes load current by virtue of a changing switch; the highspeed mechanism is a power source of the changing switch. At present, the highspeed mechanism is mainly a spring energy release device; however, a spring has poor reliability; complete paralysis will be caused once a main spring is damaged; and with the increase of use time, the elasticity of the spring will get worse and worse or broken, and that will result in serious results.